VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The star formation history and extended structure of the Hercules Milky Way satellite.' (bibcode: 2009ApJ...704..898S)
Sand, D. J. (Creator), Olszewski, E. W. (Creator), Willman, B. (Creator), Zaritsky, D. (Creator), Seth, A. (Creator), Harris, J. (Creator), Piatek, S. (Creator), Saha, A. (Creator) (2011). Photometry of the Hercules dwarf galaxy. Centre de Donnees Strasbourg (CDS). 10.26093/cds/vizier.17040898